用括号里的单词的适当形式填空。

1. How much______these pants? They are fifteen dollars. (be)

2. I'm sorry I can't remember the length of the desk. Can you tell me how______ it is? (length)

3. Can I ______ you? Yes, please. I want a T-shirt.(helpful)

4. Cindy______a new blue sweater.(have)

5. Look! The red shoes are on ______for ＄15. (sell)

隋唐以来中国封建社会出现过几个盛世，其出现的先后顺序应是：[ ]

A．“贞观之治”、“开皇之治”、“开元盛世”、“康乾盛世”

B．“开皇之治”、“贞观之治”、“开元盛世”、“康乾盛世”

C．“开元盛世”、“开皇之治”、“贞观之治”、“康乾盛世”

D．“康乾盛世”、“开皇之治”、“贞观之治”、“开元盛世”